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Mucospheres produced by a mixotrophic protist impact ocean carbon cycling


Larsson, ME and Bramucci, AR and Collins, S and Hallegraeff, G and Kahlke, T and Raina, J-B and Seymour, JR and Doblin, MA, Mucospheres produced by a mixotrophic protist impact ocean carbon cycling, Nature Communications, 13 Article 1301. ISSN 2041-1723 (2022) [Refereed Article]


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Copyright 2022 The Author(s) Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1038/s41467-022-28867-8


Mixotrophic protists (unicellular eukaryotes) that engage in both phototrophy (photosynthesis) and phago-heterotrophy (engulfment of particles)—are predicted to contribute substantially to energy fluxes and marine biogeochemical cycles. However, their impact remains largely unquantified. Here we describe the sophisticated foraging strategy of a widespread mixotrophic dinoflagellate, involving the production of carbon-rich ‘mucospheres’ that attract, capture, and immobilise microbial prey facilitating their consumption. We provide a detailed characterisation of this previously undescribed behaviour and reveal that it represents an overlooked, yet quantitatively significant mechanism for oceanic carbon fluxes. Following feeding, the mucospheres laden with surplus prey are discarded and sink, contributing an estimated 0.17–1.24 mg m−2 d−1 of particulate organic carbon, or 0.02–0.15 Gt to the biological pump annually, which represents 0.1–0.7% of the estimated total export from the euphotic zone. These findings demonstrate how the complex foraging behaviour of a single species of mixotrophic protist can disproportionally contribute to the vertical flux of carbon in the ocean.

Item Details

Item Type:Refereed Article
Keywords:mixotrophy, ocean carbon cycling, mucospheres, protist
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Phycology (incl. marine grasses)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Oceanic processes (excl. in the Antarctic and Southern Ocean)
UTAS Author:Hallegraeff, G (Professor Gustaaf Hallegraeff)
ID Code:149214
Year Published:2022
Web of Science® Times Cited:5
Deposited By:Directorate
Deposited On:2022-03-17
Last Modified:2022-10-19
Downloads:4 View Download Statistics

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